σύνειμιsýneimi

to be with: Luke 9:18, Acts 22:11.

Greek (New Testament) · G4895

Same root

σύνsýn · G4862with or together (but much closer than G3326 (μετά) or G3844 (παρά)), i.e. by association, companionship, process, resemblance, possession, instrumentality, addition, etc.
εἰμίeimí · G1510I exist (used only when emphatic)

Where it appears

Appears 2 times in the Bible.

Luke 9:18 One day Jesus left the crowds to pray alone. Only his disciples were with him, and he asked them, “Who do people say I am?”
Acts 22:11 “I was blinded by the intense light and had to be led by the hand to Damascus by my companions.

Source: G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), public domain.